U.S. patent application number 14/939675 was filed with the patent office on 2016-05-12 for cannabis fiber, absorbent cellulosic structures containing cannabis fiber and methods of making the same.
The applicant listed for this patent is FIRST QUALITY TISSUE, LLC. Invention is credited to Taras Z. ANDRUKH, Byrd Tyler MILLER, IV, Karthik RAMARATNAM, James E. SEALEY, II.
Application Number | 20160130762 14/939675 |
Document ID | / |
Family ID | 55911783 |
Filed Date | 2016-05-12 |
United States Patent
Application |
20160130762 |
Kind Code |
A1 |
RAMARATNAM; Karthik ; et
al. |
May 12, 2016 |
CANNABIS FIBER, ABSORBENT CELLULOSIC STRUCTURES CONTAINING CANNABIS
FIBER AND METHODS OF MAKING THE SAME
Abstract
A method to prepare, pulp, and bleach cannabis bast and hurd
fibers to allow for the fiber to be incorporated into absorbent
cellulosic structures on a wet-laid paper machine while keeping the
pectin within the fibers. The wet laid paper machine can use the
ATMOS, NTT, ETAD, TAD, or UCTAD method to produce the absorbent
cellulosic structure. Absorbent cellulosic structures are produced
with the cannabis bast and hurd fibers or with the bast fibers
alone with the hurd fibers being combined with paper mill sludge or
dust to form a fuel pellet.
Inventors: |
RAMARATNAM; Karthik;
(Anderson, SC) ; SEALEY, II; James E.; (Belton,
SC) ; MILLER, IV; Byrd Tyler; (Easley, SC) ;
ANDRUKH; Taras Z.; (Greenville, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FIRST QUALITY TISSUE, LLC |
Great Neck |
NY |
US |
|
|
Family ID: |
55911783 |
Appl. No.: |
14/939675 |
Filed: |
November 12, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62078737 |
Nov 12, 2014 |
|
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|
Current U.S.
Class: |
162/129 ;
162/175 |
Current CPC
Class: |
D21C 9/10 20130101; D21F
11/14 20130101; D21H 11/12 20130101; D21H 27/30 20130101; D21H
27/002 20130101; D21C 5/00 20130101; D21H 17/24 20130101 |
International
Class: |
D21H 17/24 20060101
D21H017/24; D21H 27/30 20060101 D21H027/30 |
Claims
1. A base sheet comprising cannabis fiber that contains at least
50% by weight of original amount of pectin contained in the
cannabis fiber prior to processing.
2. The base sheet of claim 1, further comprising at least three
layers, at least one of the layers comprising the cannabis
fiber.
3. The base sheet of claim 2, wherein the at least one of the
layers further comprises northern bleached softwood kraft pulp.
4. The base sheet of claim 1, wherein the base sheet forms a single
ply of a bath tissue, facial tissue or towel product.
5. The base sheet of claim 1, wherein two base sheets are plied
together to form a two ply bath or facial tissue product.
6. The base sheet of claim 5, wherein the bath or facial tissue
product has a basis weight between 20 to 45 g/m.sup.2.
7. The base sheet of claim 6, wherein the bath or facial tissue
product has a basis weight of 32 to 38 g/m.sup.2.
8. The base sheet of claim 5, wherein the bath or facial tissue
product has a caliper of 0.200 mm to 0.700 mm.
9. The base sheet of claim 8, wherein the bath or facial tissue
product has a caliper of 0.525 to 0.650 mm.
10. The base sheet of claim 8, wherein the bath or facial tissue
product has a caliper of 0.575 mm to 0.625 mm.
11. The base sheet of claim 5, wherein the bath or facial tissue
product has a machine direction tensile strength of 100 N/m to 190
N/m.
12. The base sheet of claim 11, wherein the bath or facial tissue
product has a machine direction tensile strength of 120 N/m to 170
N/m.
13. The base sheet of claim 5, wherein the bath or facial tissue
product has a cross direction tensile strength of 25 N/m to 125
N/m.
14. The base sheet of claim 13, wherein the bath or facial tissue
product has a cross direction tensile strength of 50 N/m to 100
N/m.
15. The base sheet of claim 5, wherein the bath or facial tissue
product has a ball burst of 100 to 300 grams force.
16. The base sheet of claim 15, wherein the bath or facial tissue
product has a ball burst of 175 to 275 grams force.
17. The base sheet of claim 5, wherein the bath or facial tissue
product has a lint value of 2 to 10.
18. The base sheet of claim 5, wherein the bath or facial tissue
product has a lint value of 3 to 6.
19. The base sheet of claim 5, wherein the bath or facial tissue
product has a machine direction stretch of 10% to 30%.
20. The base sheet of claim 19, wherein the bath or facial tissue
product has a machine direction stretch of 20% to 30%.
21. The base sheet of claim 5, wherein the bath or facial tissue
product has a TSA value of 80 to 120.
22. The base sheet of claim 21, wherein the bath or facial tissue
product has a TSA value of 90 to 110.
23. The base sheet of claim 5, wherein the bath or facial tissue
product has a TS7 value of 5 to 15.
24. The base sheet of claim 23, wherein the bath or facial tissue
product has a TS7 value of 7 to 10.
25. The base sheet of claim 5, wherein the bath or facial tissue
product has a TS750 value of 10 to 20.
26. The base sheet of claim 25, wherein the bath or facial tissue
product has a TS750 value of 10 to 15.
27. The base sheet of claim 1, wherein two base sheets are plied
together to form a two ply towel product.
28. The base sheet of claim 27, wherein the towel product has a
basis weight of 20 g/m.sup.2 to 70 g/m.sup.2.
29. The base sheet of claim 28, wherein the towel product has a
basis weight of 30 g/m.sup.2 to 40 g/m.sup.2.
30. The base sheet of claim 28, wherein the towel product has a
basis weight of 32 g/m.sup.2 to 38 g/m.sup.2.
31. The base sheet of claim 27, wherein the towel product has a
caliper of 0.500 mm to 1.200 mm.
32. The base sheet of claim 31, wherein the towel product has a
caliper of 0.700 mm to 1.000 mm.
33. The base sheet of claim 31, wherein the towel product has a
caliper of 0.850 mm to 1.000 mm.
34. The base sheet of claim 27, wherein the towel product has a
machine direction tensile strength of 300 N/m to 700 N/m.
35. The base sheet of claim 34, wherein the towel product has a
machine direction tensile strength of 300 N/m to 500 N/m.
36. The base sheet of claim 27, wherein the towel product has a
cross direction tensile strength of 300 N/m to 700 N/m.
37. The base sheet of claim 36, wherein the towel product has a
cross direction tensile strength of 300 N/m to 500 N/m.
38. The base sheet of claim 27, wherein the towel product has a
ball burst value of 500 grams force to 1500 grams force.
39. The base sheet of claim 38, wherein the towel product has a
ball bust value of 800 grams force to 1500 grams force.
40. The base sheet of claim 27, wherein the towel product has a
machine direction stretch of 10% to 30%.
41. The base sheet of claim 40, wherein the towel product has a
machine direction stretch of 10% to 20%.
42. The base sheet of claim 27, wherein the towel product has an
absorbency of 500 gsm to 1000 gsm.
43. The base sheet of claim 42, wherein the towel product has an
absorbency of 600 gsm to 800 gsm.
44. The base sheet of claim 27, wherein the towel product has a TSA
value of 40 to 80.
45. The base sheet of claim 44, wherein the towel product has a TSA
value of 50 to 70.
46. The base sheet of claim 1, wherein two or more base sheets are
plied together to form a multi-ply tissue or towel product.
Description
RELATED APPLICATION
[0001] This application is a non-provisional based on U.S.
Provisional Patent Application No. 62/078,737, filed Nov. 12, 2014,
the contents of which are incorporated herein by reference in their
entirety.
FIELD OF THE INVENTION
[0002] The present disclosure relates to absorbent cellulosic
structures manufactured using cannabis fibers containing
pectin.
BACKGROUND
[0003] Cannabis is a genus of flowering plants that includes three
different species, Cannabis sativa, Cannabis indica, and Cannabis
ruderalis. Cannabis has long been used for fiber (hemp), for seed
and seed oils, and recently for medicinal purposes. In the
mid-1930's, the growth of cannabis plants was outlawed in most
countries due to its usage as a recreational psychoactive drug. In
the 1970's, the ability to test and breed plants to contain low
levels of the psychoactive drug, tetra-hydro-cannabinol (THC),
became possible. Since this time, many countries have legalized the
cultivation of cannabis plants that contain low THC content (0.3%
or below). Unfortunately; during the period of prohibition;
cultivation knowledge, processing equipment, and expertise had been
optimized for other natural fibers, such as cotton, and synthetic
polymer fibers, resulting in hemp not being economically
viable.
[0004] Today, the growth and use of cannabis is extremely small and
relegated to production of the seed for sale to the food industry.
Recently, the growth of cannabis for use in the pharmaceutical
industry has begun. Although not economically feasible to grow
solely as a fiber source, the cannabis stalk (which is the fiber
source) is a waste product when grown for the seed or for the
compounds used by the pharmaceutical industry. Therefore, cannabis
can be economically competitive as a fiber source when the stalks
are harvested as a waste product from these industries.
[0005] The cannabis stalk (or stem) consists of an open cavity
surrounded by an inner layer of core fiber, often referred to as
hurd, and an outer layer referred to as the bast. Bast fibers are
roughly 20% of the stalk mass and the hurd 80% of the mass. The
primary bast fiber is attached to the hurd fiber by pectin, a glue
like substance. Cannabis bast fibers have a large range in length
and diameter, but on average are very long with medium coarseness;
suitable for making textiles, paper, and nonwovens. The hurd
consists of very short, bulky fibers, typically 0.2-0.65 mm in
length.
[0006] Cannabis fibers are hydrophobic by nature. In order for them
to be used for paper products, the fibers need to be liberated,
typically by oxidation, in order to make them hydrophilic and
suitable for use in fabricating paper using a wet laid process. In
conventional cannabis fiber preparation, the cannabis fibers are
pulped and bleached to remove the bound lignin and pectin and
further separate the fiber bundles that still exist after
decortication, the mechanical separation of the fibers in the
cannabis stalk.
[0007] Conventionally, the pulping of cannabis is usually an
alkaline process where the fibers are added to a digester under
elevated temperature and pressure with caustic chemicals (e.g.,
sodium hydroxide and sodium sulfate) until all fibers are separated
from each other. Washing with excess water removes the chemicals
and the extracted binding components. The conventional pulping
process removes the pectin from the cannabis fibers and requires a
substantial amount of water when the fibers are added to the
digester.
SUMMARY OF THE INVENTION
[0008] An object of the present invention is to provide a method of
manufacturing absorbent cellulosic structures using cannabis fibers
in which the cannabis fibers are oxidized while leaving a
substantial amount of the pectin intact and using less water than
the conventional pulping process. In an exemplary embodiment, at
least 50% by weight of the amount of original pectin is left intact
and the fibers are liberalized using at least 15 liters of water/kg
of fiber less than conventional pulping methods.
[0009] Another object of the present invention is to provide a use
for cannabis hurd fibers when only bast fibers are used for the
manufacture of paper products.
[0010] According to an exemplary embodiment of the invention,
Northern Bleached Softwood Kraft pulp is replaced wholly or in part
with cannabis bast fiber and eucalyptus fiber to lower the
manufacturing cost of absorbent cellulosic structures. In
accordance with the invention, the cannabis bast fibers are
prepared, pulped, and bleached to allow for the fiber to be
incorporated into absorbent cellulosic structures on a wet-laid
asset while retaining all or a substantial amount of the pectin
with the bast fiber. The wet laid asset can be a tissue machine for
making towel, bath tissue or facial tissue. The tissue machine may
use through air drying (TAD), or other drying technologies such as
dry creping, Structured Tissue Technology (STT), Advantage NTT,
equivalent TAD paper (ETAD), uncreped through air drying (UCTAD) or
Advanced Tissue Molding System (ATMOS), to name a few, to produce
the absorbent cellulosic structure.
[0011] The absorbent cellulosic structures of the invention have a
low basis weight and high pectin concentration and have equal
absorbency, strength, and softness compared to absorbent cellulosic
structures of higher basis weight.
[0012] Hurd fibers can be prepared together with bast fibers into
absorbent cellulosic structures in a similar fashion.
Alternatively, when the hurd fibers are not included in the wet
laid asset, they can be diverted from the decortification facility
and combined with paper mill sludge or dust to form a novel fuel
pellet composed of the cannabis hurd fibers and wood fiber, derived
from the paper mill sludge or dust.
[0013] [To be Completed Upon Completion of Claims]
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The features and advantages of exemplary embodiments of the
present invention will be more fully understood with reference to
the following, detailed description when taken in conjunction with
the accompanying figures, wherein:
[0015] FIG. 1 illustrates cannabis fiber processing via enzymatic
field retting and refining with alkali, peroxide and catalyst
pre-treatment according to an exemplary embodiment of the present
invention.
[0016] FIG. 2 illustrates cannabis fiber processing via enzymatic
field retting and co-and refining with NBSK fibers with alkali and
peroxide pretreatment according to an exemplary embodiment of the
present invention.
[0017] FIG. 3 illustrates cannabis fiber processing via enzymatic
field retting and two stage refining in the presence of peroxide
and steam according to an exemplary embodiment of the present
invention.
[0018] FIG. 4 illustrates cannabis fiber processing via enzymatic
field retting and two stage refining in the presence of peroxide
and steam, including enzymatic pre-treatment according to an
exemplary embodiment of the present invention.
[0019] FIG. 5 illustrates cannabis fiber processing via two stage
refining in the presence of peroxide and steam according to an
exemplary embodiment of the present invention.
[0020] FIG. 6 illustrates cannabis fiber processing via two stage
refining in the presence of peroxide and steam, including enzymatic
pre-treatment according to an exemplary embodiment of the present
invention.
[0021] FIG. 7 illustrates cannabis fiber processing using a twin
screw extruder according to an exemplary embodiment of the present
invention;
[0022] FIG. 8 illustrates cannabis bast and hurd fiber properties
as compared to typical softwood and hardwood fibers.
[0023] FIG. 9 illustrates the steps required for the lint testing
procedure.
[0024] FIG. 10 shows a twin screw extruder usable in various
exemplary embodiments of the present invention.
DETAILED DESCRIPTION
[0025] The headings used herein are for organizational purposes
only and are not meant to be used to limit the scope of the
description or the claims. As used throughout this application, the
words "may" and "can" are used in a permissive sense (i.e., meaning
having the potential to), rather than the mandatory sense (i.e.,
meaning must). Similarly, the words "include," "including," and
"includes" mean including but not limited to. To facilitate
understanding, like reference numerals have been used, where
possible, to designate like elements common to the figures.
[0026] The present invention is directed to the use of cannabis
fibers in the base sheet of absorbent products, such as tissue or
towel products. Such tissue and towel products may be formed using
the systems and methods described in U.S. application Ser. No.
13/837,685 (issued as U.S. Pat. No. 8,968,517); Ser. No.
14/534,631; and Ser. No. 14/561,802, the contents of which are
incorporated herein by reference in their entirety.
[0027] The first step to obtain suitable fibers from the cannabis
stalk for use in absorbent cellulosic structures such as paper
towel, bath, facial tissue, or nonwoven products is enzymatic field
retting, as shown in FIGS. 1-4. This involves letting cut cannabis
plants sit in the field with applied enzymes to degrade components
that hold the hurd and bast fibers together in the cannabis stalk.
This process improves the ability to separate the fibers in the
decortication process. The components upon which the enzymes act to
cleave molecular bonds are lignin, pectins and extractives. The
enzyme solution is engineered to be void of pectinase or other
enzymatic components that preferentially attack pectins, thereby
increasing fiber yield through this isolation process. Enzymes such
as laccase, xylanases, and lignase are preferred so as to minimize
any unwanted degradation of the fiber cellulose and hemicellulose
while keeping the pectin intact. This enzymatic retting process is
carried out under controlled conditions based on the type of
enzyme, including control of time, temperature and enzyme
concentration to maximize fiber yield and fiber physical properties
such as strength.
[0028] Next is a decortication stage, shown in FIGS. 1-7, wherein
the bast fiber is removed from the woody hurd core using a series
of steps. Some of these steps involve chopping the fiber/woody core
to smaller lengths, passing the material through one or more hammer
mills to separate bast fiber from the woody core followed by
several screens to maximize fiber separation from the woody
core.
[0029] Next is a fiber cutting stage, shown in FIGS. 1-6. During
this stage, the bast and hurd fibers are each separately cut to a
length preferably 12 mm or less. The length is critical to ensure
that the fiber does not fold upon itself or fold around other fiber
to create a fiber bundles that can plug processing equipment on the
wet laid asset. In this process the fibers are cut to the 0.5 to 20
mm range, preferably to the 3 to 8 mm range, and more preferably to
6 mm. FIG. 8 illustrates typical properties for the cannabis hurd
and bast fibers as compared to typical softwood and hardwood
fibers.
[0030] After the fiber bundles are cut to length, the bast fibers
are added alone or in combination with the hurd fibers to a
hydro-pulper with hot water (50-212.degree. F., preferably
120-190.degree. F.) at a consistency between 0.5 to 30%, preferably
between 3 to 6%, and beaten for 20-40 minutes.
[0031] After beating, the fibers are pumped to a storage chest, as
shown in FIGS. 4-6, and then to a mechanical refiner at a
controlled consistency between 2-3%. The fibers may be pumped
separately, together, or co-mixed with other wood, plant or
synthetic based fibers. The storage chest includes steam injection
and agitation to maintain the temperature set-point between
50-212.degree. F. The mechanical refiner can be a disk or conical
refiner with plates preferably designed for medium intensity
refining.
[0032] In the case of a two stage refining process, the fibers will
go through a thermo-mechanical refining (TMP) and double disc
refiner, as shown in FIGS. 4-6. The mechanical refiner can be a
disk or conical refiner with plates preferably designed for medium
intensity refining. TMP process involves refining under high
temperature and pressure with steam pressure in the range of 2 to
12 bars, preferably between 8 to 10 bars. The additional step of
TMP process further aids the lignin removal with limited pectin
removal from the fiber, providing uniform fibers for paper and
non-woven use.
[0033] The preferred energy intensity imparted to the fiber from
the refiner should be 40 to 120 kwh/ton such that the fiber bundles
are mostly separated into individual fibers.
[0034] In the final step, shown in FIGS. 1-6, the refined fibers
will go through a pressure screen to remove unprocessed fibers with
some moderate washing to remove any un-oxidized lignin and/or small
amounts of pectins that may have separated from the previous
processing steps.
[0035] During the fiber preparation process, the fibers must be
liberated, in this case through oxidation, in order for the fibers
to become hydrophilic so that they may be used in absorbent
cellulosic structures. Oxidation of the phenolic material into
muconic acids and other carboxylic acid structures in the bound
lignin, pectin, and hemicellulose will occur inside the refiner to
hydrophilize the fiber surface. The bast and hurd fiber are
preferably processed separately through the refiner, but can
optionally be co-refined together, or with other wood, plant or
synthetic fibers using the process just described.
[0036] This process may involve either alkali/enzyme, or peroxide
pretreatment as shown in FIGS. 1 through 6 and takes place either
in an air stream prior to the hydropulping step described above, or
after the hydropulping but before the refining step described
above.
[0037] This process is a water-efficient method of liberalizing the
fibers using at least 15 liters of water/kg of fiber less than
conventional pulping methods. The material to liquid ratio in this
approach is in the range of 1:1 to 1:10 compared to a material to
liquid range of 1:25 to 1:50 in conventional pulping.
[0038] For alkali treatment, the fibers will be treated with sodium
hydroxide or sodium carbonate at 1 to 10% by weight concentrations
on the weight of fibers. For enzymatic treatment, laccase, xylanase
and lignase may be used separately or in combination to degum the
fibrous materials.
[0039] In case of peroxide treatment, hydrogen peroxide or
peracetate or ozone may be used in presence of transition metal
ions some of which may include scandium, titanium, vanadium,
chromium, manganese, iron, cobalt, nickel, copper, zinc, yittrium,
zirconium, molybdenum, rhodium, palladium, silver, cadmium,
platinum, gold, mercury, etc. The transition metal ions may be
added to the hydrogen peroxide at a ratio between 1000 parts
hydrogen peroxide to 1 part catalyst to 10 parts hydrogen peroxide
to 1 part catalyst.
[0040] Peroxide treatment is carried out in alkaline conditions in
the presence of sodium hydroxide and/or sodium carbonate. Use of
hydrogen peroxide under these conditions may promote catalytic
cleavage due to the instability of hydrogen peroxide under these
conditions. Also some of the lignin compounds may be broken down
via catalytic cleavage and further oxidation. Hydrogen peroxide
addition rates may range from 0.25% by weight of fiber to 5% by
weight of fiber. Hydrogen peroxide usage may be monitored using an
Oxidation Reduction Potential (ORP) meter. The ORP meter target may
range from +350 to +500 mV at the injection point of
H.sub.2O.sub.2, preferably between +350 and +450 mV, before
refining and between +100 to +200 mV after refining to ensure
depletion of peroxide activity.
[0041] In the case of sodium hydroxide addition, base may be
controlled using an online pH probe, connected to piping after the
discharge of the refiner, to a pH set-point between 7 and 12,
preferably between 7 and 10, more preferably between 7 and 9.
[0042] Alternatively, the peroxide treatment may be carried out
under acid conditions. In that case, hydrogen peroxide mixed with a
metal catalyst such as copper (1 part catalyst to 100 parts
hydrogen peroxide) is added after urea sulfate addition near the
inlet to the refiner where the oxidation reduction potential of the
fiber slurry prior to the mechanical refiner is controlled to
between +300 and +500 mV, preferably between +350 and +450 mV, or
where the oxidation reduction potential of the fiber slurry after
the mechanical refiner is controlled to between -100 mV and -200
mV.
[0043] In the case where acid is used the acid may be controlled
using an online pH probe, connected to piping after the discharge
of the refiner, to a pH set-point between 4 and 7 in the case and
preferably between 4 and 7.
[0044] The oxidized fibers are then blended with other fibers as
necessary to create absorbent cellulosic structures with unique
properties. The oxidized fibers are blended with wood based fibers
that have been processed in any other manner such as chemical
(sulfite, kraft), thermal, mechanical, or a combination of these
techniques. The fibers could also be synthetic. When Northern
Bleached Softwood Kraft (NBSK) pulp fibers are replaced with
cannabis bast fibers, processed with the method described herein,
the tensile strength of the absorbent cellulosic structures can be
up to 100% greater. Rather than allowing the strength of the
product to increase this significantly, only a portion of the NBSK
pulp can be replaced and the tensile strength brought back to
target by either decreasing the basis weight, decreasing overall
refining, or substituting some of the remaining NBSK with weaker
short fiber such as eucalyptus or cannabis hurd fiber.
[0045] FIG. 7 shows a fiber processing method according to a
preferred exemplary embodiment of the present invention. In this
process, decortication and (optionally) enzymatic field retting are
performed as described above. However, rather than separate cutting
and pre-treatment steps (including oxidation of the fibers through
alkali/enzyme, or peroxide pretreatment), these steps may be
combined together through the use of a twin screw extruder, as
described in U.S. Pat. Nos. 4,088,528 and 4,983,256 and EP 0979895
A1, the contents of which are incorporated herein by reference in
their entirety. Alternatively, a twin screw extruder is used only
for the cutting step, and the pre-treatment step is performed
separately. Although the process shown in FIG. 7 does not show a
separate refining step, it should be appreciated that the process
may include mechanical and/or thermo-mechanical refining of the
fibers as described with reference to FIGS. 1-6.
[0046] FIG. 10 illustrates a conventional twin screw extruder,
generally designated by reference number 50, that may be used in
exemplary embodiments of the present invention. The twin screw
extruder 50 includes two parallel screws (only one screw 60 is
shown in FIG. 10) driven to rotate about their axes within an
elongate enclosure. The screws are provided with helical threads
which engage one another as the screws rotate. The unprocessed
fiber is provided to the twin screw extruder 50 through inlet
opening 51 and the rotation of the screws causes advancement of the
fibers towards outlet opening 52. The compression and shear forces
within the twin screw extruder 50 result in grinding of the fibers.
Further, as the fibers advance through the twin screw extruder 50,
they may be subjected to heat and/or chemical treatment by heating
elements 71, 72, 73 and through introduction of chemical reagents
through openings 53, 54, 57. Waste may be collected through
openings 55, 56 and either disposed of or recycled. By varying the
temperature, chemical mixture and orientation of the threads along
the screw lengths, various fiber treatment zones I, II, III, IV and
V are created along the length of the twin screw extruder 50.
[0047] The fiber slurry produced as described with reference to
FIGS. 1-7 is then supplied to a headbox to manufacture absorbent
cellulosic structures on a wet laid asset such as any of the type
used to produce tissue products such as conventional, ATMOS, NTT,
ETAD, TAD, or UCTAD wet laid machines.
[0048] Each of the processing steps described above can be used as
a stand-alone processing step or the steps can be done in any
combination.
[0049] Produced tissue products include bath tissue, facial tissue
or towel product containing cannabis bast or hurd fibers.
[0050] The bath or facial tissues can be 1, 2, or 3 ply products,
preferably 2-ply products with a basis weight between 20 to 45
g/m.sup.2, preferably 30 to 40 g/m.sup.2, and more preferably 32 to
38 g/m.sup.2.
[0051] The bath or facial tissue products have a caliper between
0.200 mm and 0.700 mm, preferably between 0.525 mm and 0.650 mm,
and most preferably between 0.575 mm and 0.625 mm.
[0052] The bath or facial tissue products have an MD tensile
between 190 N/m and 100 N/m, preferably between 170 and 120 N/M and
a CD tensile of between 125 N/m and 25 N/m, preferably between 50
and 100 N/m.
[0053] The bath or facial tissue products have a ball burst between
100 and 300 grams force, preferably between 175 and 275 grams
force.
[0054] The bath or facial tissue products have a lint value between
2 and 10, preferably between 3 to 6.
[0055] The bath or facial tissue products have an MD stretch
between 10 and 30%, preferably between 20 and 30%.
[0056] The bath or facial tissue products have a TSA between 80 and
120, preferably between 90 and 110, a TS7 value between 5 and 15,
preferably between 7 and 10, and a TS750 between 10 and 20,
preferably between 10 and 15.
[0057] The towel product has a basis weight from 20 to 70
g/m.sup.2, preferably 30 to 40 g/m.sup.2, and more preferably 32 to
38 g/m.sup.2.
[0058] The towel product has a caliper between 0.500 mm and 1.200
mm, preferably between 0.700 mm and 1.000 mm, and most preferably
between 0.850 and 1.000 mm.
[0059] The towel product has an MD tensile between 300 N/m and 700
N/m, preferably between 300 and 500 N/m and a CD tensile of between
300 N/m and 700 N/m, preferably between 300 and 500 N/m.
[0060] The towel product has a ball burst between 500 and 1500
grams force, preferably between 800 and 1500 grams force.
[0061] The towel product has an MD stretch between 10 and 30%,
preferably between 10 and 20%.
[0062] The towel product has an absorbency between 500-1000 gsm,
preferably between 600-800 gsm.
[0063] The towel product has a TSA between 40 to 80, preferably
between 50 and 70.
[0064] When the hurd fiber is not combined with the bast fiber and
incorporated into an absorbent cellulosic structure, the hurd fiber
can be combined with paper waste from a paper mill. Paper mill
sludge has a significant water content (over 10%) and it is
uneconomical to dry it sufficiently to be utilized as a fuel
source. Therefore the sludge is usually disposed of as a waste
product. The sludge is usually obtained by clarifying and
dewatering the solids from the paper mill waste water stream. The
solids obtained are usually over 95% cellulosic based fiber.
[0065] Hurd fiber can be combined with sludge removed from waste
water to form a precursor material for conversion into fuel
pellets. Paper dust may also be collected and combined with the
hurd fiber prior to adding the sludge. The precursor material can
then be sent through a fuel pelletizer to obtain a pellet with a
moisture content below 10%, a requirement for most commercially
sold fuel pellets.
Softness Testing
[0066] Softness of a 2-ply tissue web was determined using a Tissue
Softness Analyzer (TSA), available from EMTECH Electronic GmbH of
Leipzig, Germany. A punch was used to cut out three 100 cm.sup.2
round samples from the web. One of the samples was loaded into the
TSA, clamped into place, and the TPII algorithm was selected from
the list of available softness testing algorithms displayed by the
TSA. After inputting parameters for the sample, the TSA measurement
program was run. The test process was repeated for the remaining
samples and the results for all the samples were averaged. A TSA
(overall softness), TS7 (bulk structure softness), and TS750
(surface structure softness) reading are obtained.
Ball Burst Testing
[0067] Ball Burst of a 2-ply tissue web was determined using a
Tissue Softness Analyzer (TSA), available from EMTECH Electronic
GmbH of Leipzig, Germany using a ball burst head and holder. A
punch was used to cut out five 100 cm.sup.2 round samples from the
web. One of the samples was loaded into the TSA, with the embossed
surface facing down, over the holder and held into place using the
ring. The ball burst algorithm was selected from the list of
available softness testing algorithms displayed by the TSA. The
ball burst head was then pushed by the EMTECH through the sample
until the web ruptured and the grams force required for the rupture
to occur was calculated. The test process was repeated for the
remaining samples and the results for all the samples were
averaged.
Stretch & MD, CD, and Wet CD Tensile Strength Testing
[0068] An Instron 3343 tensile tester, manufactured by Instron of
Norwood, Mass., with a 100N load cell and 25.4 mm rubber coated jaw
faces was used for tensile strength measurement. Prior to
measurement, the Instron 3343 tensile tester was calibrated. After
calibration, 8 strips of 2-ply product, each one inch by four
inches, were provided as samples for each test. For testing MD
tensile strength, the strips are cut in the MD direction and for
testing CD tensile strength, the strips are cut in the CD
direction. One of the sample strips was placed in between the upper
jaw faces and clamp, and then between the lower jaw faces and clamp
with a gap of 2 inches between the clamps. A test was run on the
sample strip to obtain tensile and stretch. The test procedure was
repeated until all the samples were tested. The values obtained for
the eight sample strips were averaged to determine the tensile
strength of the tissue. When testing CD wet tensile, the strips are
placed in an oven at 105.degree. C. for 5 minutes and saturated
with 75 microliters of deionized water immediately prior to pulling
the sample.
Lint Testing
[0069] FIG. 9 describes a lint testing procedure using a
Sutherland.RTM. 2000.TM. Rub tester, manufactured by Danilee Co.,
of San Antonia, Tex., USA.
Basis Weight
[0070] Using a dye and press, six 76.2 mm by 76.2 mm square samples
were cut from a 2-ply product being careful to avoid any web
perforations. The samples were placed in an oven at 105.degree. C.
for 5 minutes before being weighed on an analytical balance to the
fourth decimal point. The weight of the sample in grams is divided
by 0.0762 m.sup.2 to determine the basis weight in
grams/m.sup.2.
Caliper Testing
[0071] A Thwing-Albert ProGage 100 Thickness Tester, manufactured
by Thwing Albert of West Berlin, N.J., USA was used for the caliper
test. Eight 100 mm.times.100 mm square samples were cut from a
2-ply product. The samples were then tested individually and the
results were averaged to obtain a caliper result for the base
sheet.
Absorbency Testing
[0072] An M/K GATS (Gravimetric Absorption Testing System),
manufactured by M/K Systems, Inc., of Peabody, Mass., USA was to
test the absorbency of the two-ply product.
[0073] In accordance with one exemplary embodiment, tissue made on
a wet-laid asset with a three layer headbox is produced using the
through air dried method. A Prolux 005 TAD fabric design supplied
by Albany International Corp. of Rochester, N.H., USA, is utilized.
The fabric is a 5 shed design with a warp pick sequence of
1,3,5,2,4, a 17.8 by 11.1 yarn/cm Mesh and Count, a 0.35 mm warp
monofilament, a 0.50 mm weft monofilament, a 1.02 mm caliper, with
a 640 cfm and a knuckle surface that is sanded to impart 27%
contact area with the Yankee dryer. The flow to each layer of the
headbox is about 33% of the total sheet. The three layers of the
finished tissue from top to bottom are labeled as air, core and
dry. The air layer is the outer layer that is placed on the TAD
fabric, the dry layer is the outer layer that is closest to the
surface of the Yankee dryer and the core is the center section of
the tissue. The tissue is produced with 45% eucalyptus, 55% NBSK
fiber in the air layer; 50% eucalyptus, 25% NBSK, and 25% bast
cannabis fiber in the core layer; and 100% eucalyptus fiber in the
dry layer.
[0074] The cannabis bast fiber is prepared as shown in FIG. 1 by
cutting decorticated bast fibers to 6 mm length, beating the fiber
at 4% consistency in a pulper using 190.degree. F. water for 30
minutes. The slurry is then pumped to a holding tank with steam
injection to hold the slurry temperature to 190.degree. F. before
being pumped to a conical refiner model RGP 76 CD supplied by
Valmet Corporation of Espoo, Finland.
[0075] The bast fibers are oxidized using one of two methods. Using
the standard alkaline control process, the pH of the slurry is
controlled with sodium hydroxide injection to the suction of the
pump supplying the refiner to a pH of 8. Alternatively, the pH of
the slurry is controlled with sodium hydroxide injection to the
suction of the pump supplying the refiner to a pH within a range of
7-12, preferably within a range of 7-10, and more preferably the pH
is 8. Hydrogen peroxide is added after sodium hydroxide addition
near the inlet to the refiner and controlled by using ORP
(oxidation reduction potential) meter to control to an ORP
set-point between +350 and +500 mV at the injection point of
H.sub.2O.sub.2 (before refining) and target +100 to +200 mV after
refining to ensure depletion of peroxide activity.
[0076] In the case where sodium hydroxide is added, hydrogen
peroxide mixed with a metal catalyst such as copper (1 part
catalyst to 100 parts hydrogen peroxide) is added after sodium
hydroxide addition near the inlet to the refiner and controlled by
an ORP (oxidation reduction potential) probe at the discharge of
the refiner to a target range of +100 to +200 mV.
[0077] Using the acid control process, the pH of the slurry is
controlled with urea sulfate injection to the suction of the pump
supplying the refiner to a pH within a range of 6-7, preferably
within a range of 5-7 and more preferably the pH is 5.
[0078] In the case where urea sulfate is added, hydrogen peroxide
mixed with a metal catalyst such as copper (1 part catalyst to 100
parts hydrogen peroxide) is added after urea sulfate addition near
the inlet to the refiner where the oxidation reduction potential of
the fiber slurry prior to the mechanical refiner is controlled to
between +300 and +500 my, preferably between +350 and +450 mV, or
where the oxidation reduction potential of the fiber slurry after
the mechanical refiner is controlled to between -100 mV and -200
mV.
[0079] The refining energy imparted to the fiber slurry is 80
kwh/ton. The bast fiber is then added to the core layer blend chest
where it is mixed with the NBSK, processed separately, before being
pumped and diluted through a fan pump to feed the middle layer of
the 3-layer headbox.
[0080] The tissue, according to the first exemplary embodiment, is
produced with chemistry described in U.S. patent application Ser.
No. 13/837,685, the contents of which are incorporated herein by
reference, with addition of a temporary wet strength additive,
Hercobond 1194 (supplied by Ashland of Wilmington, Del., USA) to
the air layer, a dry strength additive, Redibond 2038 (supplied by
Corn Products, of Bridgewater, N.J., USA) split 75% to the air
layer, 25% to the dry layer, and a softener/debonder, T526
(supplied by EKA Chemicals Inc., of Marietta, Ga., USA) added in
combination to the core layer. The T526 is a softener/debonder
combination with a quaternary amine concentration below 20%.
[0081] The tissue is then plied together to create a rolled 2-ply
sanitary tissue product with 190 sheets, a roll firmness of 6.5, a
roll diameter of 121 mm, with sheets having a length and width of
4.0 inches. The 2-ply tissue product further has the following
product attributes: basis weight of 37 g/m.sup.2, caliper of 0.610
mm, MD tensile of 150 N/m, CD tensile of 90 N/m, a ball burst of
240 grams force, a lint value of 5.5, an MD stretch of 18%, a CD
stretch of 6%, a CD wet tensile of 14 N/m, a TSA of 93, a TS7 of
8.5, and a TS750 of 14.
[0082] In a second exemplary embodiment, the product is made in the
same manner as the first exemplary embodiment, resulting in the
same physical properties of the 2-ply tissue roll. The only
exception being that the cannabis bast and NBSK fiber are processed
through the refiner together with 40 kwh/ton energy intensity as
shown in FIG. 2. Since processed together, the slurry mixture is
roughly 25% bast fiber, 75% NBSK which is then pumped to the core
and air layer blend chest. The final fiber distribution is 100%
eucalyptus to the Yankee layer, with the air and core layer being
47.5% eucalyptus, 12.5% bast, and 40% NBSK.
[0083] In another exemplary embodiment, the product is made in the
same manner as the first exemplary embodiment except the Yankee
layer fiber content is 90% eucalyptus and 10% cannabis hurd fiber.
The hurd fiber is processed separately in the manner described in
the first exemplary embodiment but with an energy intensity of 30
kwh/ton provided by a separate refiner.
[0084] In another exemplary embodiment, paper towel made on a
wet-laid asset with a three layer headbox is produced using the
through air dried method. A TAD fabric design described in U.S.
Pat. No. 5,832,962 and supplied by Albany International Corp. of
Rochester, N.H., USA was utilized. The fabric is a 13 shed design
with 12.0 yarn/cm Mesh and Count, a 0.35 mm warp monofilament, a
0.50 mm weft monofilament, a 1.29 mm caliper, with a 670 cfm and a
knuckle surface that is sanded to impart 12% contact area with the
Yankee dryer. The flow to each layer of the headbox is about 33% of
the total sheet. The three layers of the finished tissue from top
to bottom are labeled as air, core and dry. The air layer is the
outer layer that is placed on the TAD fabric, the dry layer is the
outer layer that is closest to the surface of the Yankee dryer and
the core is the center section of the tissue. The tissue is
produced with 20% eucalyptus, 15% cannabis bast fiber, and 65%
NBSK. The Yankee layer fiber is 50% eucalyptus, 50% NBSK. Polyamine
polyamide-epichlorohydrin resin at 10 kg/ton (dry basis) and 4
kg/ton (dry basis) of carboxymethyl cellulose are added to each of
the three layers to generate permanent wet strength.
[0085] The cannabis fiber is prepared using the process described
in FIG. 4. Following the decortication step, the decorticated bast
fibers are cut to 6 mm length, beating the fiber at 4% consistency
in a pulper at a temperature of 190.degree. F. for 30 minutes. The
slurry is then pumped to a holding tank with steam injection to
hold the slurry temperature to 190.degree. F. before being pumped
to a conical refiner model RGP 76 CD supplied by Valmet Corporation
of Espoo, Finland.
[0086] The bast fibers are oxidized using one of two methods. Using
the standard alkaline control process, the pH of the slurry is
controlled with caustic injection to the suction of the pump
supplying the refiner. Hydrogen peroxide is added after caustic
addition near the inlet to the refiner and controlled by using ORP
(oxidation reduction potential) meter to control to an ORP
set-point between +350 and +500 mV at the injection point of
H.sub.2O.sub.2 (before refiner) and target +100 to +200 mV after
refining to ensure depletion of peroxide activity.
[0087] Using the acid control process, the pH of the slurry is
controlled with sulfuric acid injection to the suction of the pump
supplying the refiner. Hydrogen peroxide and a metal catalyst such
as iron (1 part catalyst to 100 parts hydrogen peroxide) is added
after acid addition near the inlet to the refiner where the
oxidation reduction potential of the fiber slurry prior to the
mechanical refiner is controlled to between +300 and +500 mV,
preferably between +350 and +450 mV, or where the oxidation
reduction potential of the fiber slurry after the mechanical
refiner is controlled to between -100 mV and -200 mV.
[0088] The refining energy imparted to the fiber slurry is 80
kwh/ton. The bast fiber is then added to the core and air layer
blend chests where it is mixed with the NBSK and eucalyptus,
processed separately, before being pumped and diluted through fan
pumps to feed two layers of the 3-layer headbox.
[0089] The towel is then plied together to create a rolled 2-ply
product with 142 sheets, a roll diameter of 142 mm, with sheets
having a length of 6.0 inches and a width of 11 inches. The 2-ply
tissue product further has the following product attributes: basis
weight of 39 g/m.sup.2, caliper of 0.850 mm, MD tensile of 385 N/m,
CD tensile of 365 N/m, a ball burst of 820 grams force, an MD
stretch of 18%, a CD stretch of 6%, a CD wet tensile of 105 N/m, an
absorbency of 750 gsm, and a TSA of 53.
* * * * *